(i) Field of the Invention
The present invention relates to an improvement in or relating to an off-road vehicle equipped with endless articulated steel band, and more particularly to an improved endless articulated steel band vehicle for off-road services which is equipped with an endless articulated steel band and is specifically adaptable to the running operations on the wilds and muddy grounds.
(ii) Description of the Prior Art
It is generally known that there has been developed saddle-type four-wheeled vehicles adaptable for the operations on the muddy grounds, roughs and wilds, which are designed with a similar basic frame construction to that of a two-wheeled vehicle or motor cycle.
Among such vehicles for the off-road services, there are known developed some ones which are equipped with the rear balloon tires having endless articulated steel band mounted around the circumference thereof for the operations on the sandy grounds or for the services on the snowy wilds in the winter season. Also, there are some others with four rear wheels having a endless belt extending across the two rear wheels on the each side of a vehicle.
FIG. 12 shows in general perspective view an off-road service vehicle having an endless articulated steel band drive equipped in the rear part of the main frame structure, which has been proposed in the prior application filed by the instant inventors.
According to this particular construction, the off-road vehicle is seen comprising a main frame complete of saddle-riding type as designated at the reference numeral 100, to which main frame there are provided two front wheels as designated at 101 and two rear wheels at 102, each of these rear wheel having an endless articulated steel band drive 103 mounted operatively thereon. More specifically, it is seen from the Figure that the endless articulated steel band drive 103 comprises two swing arms 104, 105 mounted swingably at the lower pivot axis of the main frame 100, a suspension units 106, 107 for suspending these swing arms from the main frame 100, a rear wheel 109 mounted rotatably by the swing arm 104 through a drive shaft 108 extending outwardly, an idle wheel 111 held rotatably by the swing arm through an idle shaft 110, and an endless belt 112 mounted extending across the rear wheel 109 and the idle wheel 111.
With this construction, this vehicle is well adaptable to the running operations following the irregular ground surfaces of the roughs and wilds, with the equipment of this rubber endless belt 112 mounted operatively across the rear wheel 109 and the idle wheel 111.
Incidentally, this vehicle is equipped with a steering handle of bar type designated at 113, which is adapted to the steering operation of the front wheels 101.
Now, referring to the conventional off-road service vehicles having the articulated steel band drive of such a construction as noted above, while the articulated steel band drive of this type may be afforded with a relatively simple construction making use of the existing rear drive axis and wheel mechanism, it was then inevitable that this construction may make longer the overall length of a vehicle, thus resulting in an undesirably substantial vehicle extension, because of the employment of an idle wheel 111 having a similar dimension which has to be mounted in a further rear position of the rear wheel 109.
Besides, in the general construction of such an off-road vehicle of articulated steel band drive type, there are some that have no differential gears equipped in the power train of the drive shaft 108 for the rear wheel 109 in an attempt to cut the production cost short, in which case their turning characteristics turned naturally to be sacrificed.
In addition, according to the conventional construction of a vehicle having the rear articulated steel band drive, when it is put to run on the soft and unstable grounds like in a fresh coat of snow or in sands, the vehicle cannot possibly get out of captures at its gears and move any further because of its shortage in the lift effect of such drive.
Furthermore, with the vehicle having the articulated steel band drive of such conventional construction, there may possibly occur a substantial looseness in the articulated steel band drive due to the irregularities and roughness in the ground surface, thus affecting the adhesion effect of the drive like a slippage or a loss of drive.
In view of such drawbacks as encountered in the conventional construction of the off-road vehicle of articulated steel band drive type, the present invention is essentially directed to the provision of an improved construction of a rear articulated steel band drive mechanism for use in a vehicle of saddle riding type for the irregular ground services.